Isolation Amplifier
Isolation amplifiers provide electrical isolation and an electrical safety barrier. They protect data acquisition components from common mode voltages, which are potential differences between instrument ground and signal ground. Instruments that are applied in the presence of a common mode voltage without an isolation barrier allow ground currents to circulate, leading in the best case to a noisy representation of the signal under investigation. In the worst case, assuming that the magnitude of common mode voltage or current is sufficient, instrument destruction is likely. Isolation amplifiers are used in medical instruments to ensure isolation of a patient from power supply leakage current.
Amplifiers with an isolation barrier allow the front-end of the amplifier to float with respect to common mode voltage to the limit of the barrier's breakdown voltage, which is often 1,000 volts or more. This action protects the amplifier and the instrument connected to it, while still allowing a reasonably accurate measurement.
These amplifiers are also used for amplifying low-level signals in multi-channel applications. They can also eliminate measurement errors caused by ground loops. Amplifiers with internal transformers eliminate external isolated power supply. They are usually used as analogue interfaces between systems with separated grounds.
Isolation amplifiers may include isolated power supplies for both the input and output stages, or may use external power supplies on each isolated portion.
Read more about Isolation Amplifier: Operating Principles, Amplifier Selection Guidelines
Famous quotes containing the word isolation:
“One of the most significant effects of age-segregation in our society has been the isolation of children from the world of work. Whereas in the past children not only saw what their parents did for a living but even shared substantially in the task, many children nowadays have only a vague notion of the nature of the parent’s job, and have had little or no opportunity to observe the parent, or for that matter any other adult, when he is fully engaged in his work.”
—Urie Bronfenbrenner (b. 1917)